Honestly, I think the whole "video games are like movies" metaphor is entirely broken. Sure, introducing voices to movies made a big difference. However, would the same hold true for.. books? Board games? Why should we expect it to hold true for video games, which borrow liberally from virtually every form of media and gaming out there?

"Text-based dialogue in games today is almost exclusively about budget constraints - and not an artistic choice.

I find it surprising that anyone would argue otherwise, actually. "
Ask Nintendo about this. You know. Nintendo. The biggest and most successful video game developer in the world. They have been highly resistant to using voice acting for anything except character-originated sound effects. Almost none of their games use voice acting for dialogue, and it has nothing to do with budget, as some of these games are among the highest selling games of all time. They argue that voice acting creates a barrier between the player and the character, even in more RPG-ish leaning games such as the Zelda series.

Of course, you could respond, "Well, that's Mario and such. Of course those games don't need dialogue to be immersive." However, that's exactly my point. If you have a game that is openly emulating movies, with a linear storyline, a strong emphasis on narrative and the like, then voice acting might be appropriate. However, that doesn't mean it's always necessary or even positive. Simply put: games aren't movies, so not all games will be improved by the same things that improve movies.

You could argue that, at the least, RPGs might gain more from voice acting than other genres, but, again, it depends on the type of RPG. A Bioware-esque RPG might gain from it, but a game that focuses on being dynamic or claustrophobic or incredibly large and varied may not. Sometimes, the introduction of voice acting might be preferable, but, as you implicitly note, it might take too much budget for the good it does. However, since voice acting necessarily imposes more of a structure on a game than text, voice acting may actually be a -bad- thing for RPGs hoping to emphasis dynamic or procedurally generated content. It all depends on what you're looking for and what your vision is.

For what it's worth, I enjoy plenty of games with voice acting and plenty without it. Avernum 1's newest remake was my most played RPG of 2012 despite having no voice acting and little in the way of graphics. (Let me note here that this was my first Spiderweb game, and I don't exactly have a deep history with indie or hardcore PC RPGs. This was a very pleasant surprise!) However, recent games like Dragon Age Origins, Skyrim, and Fallout New Vegas are also personal favorites.

As in the previous discussion about Dark Souls, I think designers should focus on the essence of a game rather than checking boxes off on the cover. Use voice acting when it makes sense, but don't waste the resources or limit a game's dynamism when it doesn't.